


Crossing Paths

by mew_tsubaki



Series: mew's cousins AU [2]
Category: Haikyuu!!, Kuroko no Basuke | Kuroko's Basketball
Genre: Kasamatsu is too pure for my heart, M/M
Language: English
Status: Completed
Published: 2016-08-23
Updated: 2016-08-23
Packaged: 2018-08-10 16:24:53
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,137
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7852480
Author URL: https://archiveofourown.org/users/mew_tsubaki/pseuds/mew_tsubaki
Summary: <blockquote class="userstuff">
              <p>Post-spring high, light spoilers for Extra Game. "They don't see things through the eyes of their respective idiot partners." -—Or, cousins Iwaizumi and Kasamatsu accidentally let two prima donnas meet. *Set after "Mutual Hate" & followed by "Jealousy."</p>
            </blockquote>





	Crossing Paths

**Author's Note:**

> The Haikyuu! characters belong to Furudate Haruichi-sensei and the Kuroko no Basuke characters to Fujimaki Tadatoshi-sensei, not to me. I swear, Iwaizumi and Kasamatsu being cousins is perfect. XD Read, review, and enjoy! *Note: Set after "Mutual Hate," but you don't have to read that to enjoy this. You might like to, though. :]

It feels kinda strange, not having seen Yukio in so long.

But Iwaizumi supposes that's how things are, now that they've graduated from high school and are beginning university. It's a change of venue for them, so other things are bound to change.

"Iwa- _chaaan_!"

Well, most other things.

Oikawa still dogs his heels, and Iwaizumi would be lying if he said he weren't impressed. Oikawa isn't as bad as he used to be since he finally toned it down, and Iwaizumi likes that. He likes the Oikawa Tooru who will pout at him and get genuinely angry with him and can just chill when they're doing homework for one of their classes. He likes it all because it means Oikawa's being his real self around his childhood friend, and that's all Iwaizumi ever wanted from him.

(That's all, he swears, even as his mind flashes back to last night as he tries to remember the movie they were watching in their dorm room, and he can't recall a lick of it because Oikawa was feeling extra friendly and Iwaizumi couldn't see the screen with Oikawa's tongue down his throat.)

Oikawa leans against a pole by the train's doors and eyes him, and that annoying smirk slides onto his face. "…Iwa-chan, what are you thinking about?"

Iwaizumi smacks him in the arm, and he looks away. He can see in the window's reflection that his face is red, and he'll be damned if he tells Oikawa why. Though he knows Oikawa is more than sharp enough to know he's the root of all evil.

Still, the idol takes some credit for not pushing the subject in public. As Iwaizumi's noticed, Oikawa's done a much better job of maturing.

The former spiker for Seijou clears his throat, calms down. "So, after all this time, you actually need new sneakers?"

"Mm-hmm," Oikawa replies. He stands up straight as the train slows down, announcing its arrival in Shibuya. "My old ones are pretty worn, so if I wanna play for our uni, I've gotta get new ones."

"Wow. I still can't believe it since the game isn't really hard on shoes. You've had those since we started at Seijou—you going to toss the old ones?"

"Hell no!" Oikawa is clearly offended by the thought. "Just because Tobio-chan won in the end doesn't mean I'll toss them! I still kicked his ass more than a year ago at the Interhigh prelims." He snorts derisively. "If anything, I should cast those sneakers in bronze."

Iwaizumi rolls his eyes and smacks the taller man on the back of his head. "Dumbass. Stop hating Kageyama. We've got a new team, and there's no Kageyama in sight." Oikawa's quiet. "Oikawa…"

He sticks his tongue out at Iwaizumi. "There's always another Tobio-chan. Personally, I think that fellow first year guy who looks good to be the reserve setter—"

Iwaizumi covers Oikawa's mouth with his hand. "Don't even go there."

Unfortunately, the "mature" Oikawa has learned a few tricks, and he stares openly at the other male before he licks his hand.

Iwaizumi swallows a yelp and gives him a glare, yanking his hand away and wiping it on Oikawa's sweatshirt. "Shittykawa!"

Oikawa smirks in response. "I win~"

Sometimes, Iwaizumi really wishes Yukio had joined them at T Uni.

If Iwaizumi were lucky, he muses as they get off and exit the station, then he'd have both Oikawa and Yukio with him in university. Those two aren't alike, but they almost cancel each other out around Iwaizumi—though it's not to say that Yukio needs to be balanced out. Only Oikawa does.

Iwaizumi makes some plans while Oikawa chatters about their surroundings (he loves living in the city, he's such a kid, though Iwaizumi won't tell him that he finds that cute). Yukio's supposedly studying at A Uni, just outside the city limits. So maybe once Iwaizumi's had some time to get used to his schedule, he can work in hanging out with his cousin. He tells Oikawa as much as the familiar 109 building comes into view.

"Yukio-chan?" Oikawa asks.

"Yes, him, and stop calling him that." They may have all played together when they were little, but it's always bothered Iwaizumi that Oikawa and Yukio use their given names so easily with each other. "Oikawa," "Assikawa," and "Shittykawa" are all fine in Iwaizumi's book. "But I think it'd be nice, to spend time together like before."

Oikawa shakes his head.

The spiker doesn't understand. "What? You suddenly don't like him?"

"No, Iwa-chan—" Oikawa points, and they stop on the sidewalk. "Isn't that Yukio-chan over there?"

Is it? Iwaizumi looks to where his friend aims, and…well, he'd be damned if he didn't think that looked exactly like Kasamatsu Yukio. They cross the street, and Yukio notices them before they reach him.

"Hajime!" Yukio smiles. "Tooru. How are you guys?"

Iwaizumi internally breathes a sigh of relief. It's almost as if thinking of him actually summoned him. Iwaizumi jostles the younger male's shoulder in a friendly way. "Fine. I haven't heard from you in forever."

Yukio shakes his head. "You exaggerate. I called you back in…"

"April."

"…April when I got the deferred acceptance letter. And I called you in…"

"June."

"…June for your birthday. And I've emailed you a few times since then!"

Iwaizumi chuckles. "You have. Have you tried out for your school's basketball team yet?"

Yukio runs a hand through his short black hair. "Yeah. Unsurprisingly, I'm not a starter. But I get it—seniority matters. I'm okay with that." His steel blue eyes dart around, as if he can't give them his whole attention.

Oikawa snickers. "Are we keeping you from something, Yukio-chan?"

Surprisingly, Yukio's face…reddens? "No," he's too quick to blurt.

Iwaizumi and Oikawa exchange a glance. They're the two people in the world who have known Yukio the longest, so they know just how bad a liar the basketball player is.

Before Yukio can scramble out an explanation, someone else approaches them. He's tall—taller even than Oikawa—blond, good-looking, and he has his left ear pierced with a black hoop. He's dressed fashionably, too, like Oikawa when he's trying to please his fans. And his face is familiar.

"Senpai's friends?" he babbles, looking at Yukio.

Yukio's flush deepens, and whatever he tries to say comes out a garbled mess.

The blond has some manners. He holds out his hand to Iwaizumi. "Kise Ryouta! I'm Kasamatsu-senpai's kouhai!"

Thought so. Iwaizumi's seen his face in magazines, but he definitely looks different now, with the shorter haircut and older face.

Oikawa sizes him up. "So you're Kise of the Vorpal Swords."

Kise doesn't react. "Kaijou's Kise," he calmly corrects, and Yukio turns a newer, more brilliant shade of red.

"And Yukio-chan's Oikawa Tooru, I bet."

"Oikawa Tooru? Who's that?" Kise means no harm, judging by his puppy-like eyes and smile.

The setter turns to Iwaizumi. "Iwa-chan…"

Shit. Iwaizumi knows that look. Oikawa is already putting Kise in the same category as Kageyama. And _that_ is going to be a pain in the ass to deal with.

Again, thank god for Yukio. "Iwaizumi Hajime, my cousin," he interrupts as he gestures to them for Kise's reference. "And his best friend, my childhood friend, Oikawa Tooru." He gives Oikawa an exasperated look. "And _who's_ my Oikawa Tooru?"

Oikawa smiles and shrugs, but his focus is on the newcomer, and Oikawa is not one to be outshone. "So, Kise Ryouta-chan…"

"Oikawa," Iwaizumi warns.

But some understanding surprisingly passes between Oikawa and Kise. The blond draws himself up to his full height. "Yes?"

"How close are you to Yukio-chan here?"

"Very," Kise replies.

Iwaizumi gives his cousin a look, and Yukio just sighs and shakes his head. They don't see things through the eyes of their idiot respective partners.

"And you and Iwaizumi-san?" Kise goads.

Oikawa slings an arm around Iwaizumi's shoulders and leans his head in close by Iwaizumi's ear. He smirks. " _Very_ ," he answers.

"Knock it off," the spiker chides, and he shoves Oikawa away. He misses the smirk Kise shoots backs at Oikawa, and when he goes to ask Yukio if maybe they should grab lunch together to let these two dorks finish their "introductions," all hell breaks loose behind them as the cousins lead the way, half looking to eat and catch up, half looking to escape the other two and feign knowing them.

"I've heard of you, but only because of those other _kids_ in the Generation of Miracles," Oikawa taunts.

"Funny. I've never heard of you at all," Kise reminds him.

" _I've_ been with Iwa-chan since elementary school."

"Well… _I've_ been with Kasamatsu-senpai for over a year. He's the only one who can kick me around!"

"Only Iwa-chan is allowed to punch me!"

Iwaizumi wants to dig a hole for himself and be buried in it. Judging by Yukio's expression, his cousin wishes to do the same for himself.

"Iwa-chan and I are the same age and will always be together, basketball pretty boy."

Kise makes a sound as though Oikawa's words literally strangle him. "W-Well…! Senpai and I will always be…together…" He lunges forward and hugs Yukio's arm to him. "Won't we, senpai?!"

Oikawa looks pleased with himself now that Kise's nearly crying in public, so Iwaizumi drops back a step to let Yukio calm his kouhai down and to talk some sense in Oikawa. "Hey. You're being a gigantic brat right now."

"It's important to establish who's top dog around here," Oikawa remarks with a shrug.

Iwaizumi punches his arm—not too hard, but hard enough to bring Oikawa back down to Earth. "I said, _hey_. There's no need to compete. You're both idiots and Yukio and I have to put up with each of you, but otherwise you two are vastly different." He pauses, realizes a trace of uncertainty on Oikawa's face, and gives him a questioning look. "What?"

"…so, just because you've been introduced to a younger version of me, you won't be taken away?"

"God, you're stupid. I'm not going anywhere, Shittykawa."

The setter eases up, and he seems to draw strength from placing his hand on the small of Iwaizumi's back for a brief moment when the foursome enters a fast food restaurant. Even though Iwaizumi's mind instantly brings up recent memories of just how close the two have been since sharing a dorm room, he keeps himself under control.

"I really hate you, Assikawa…"

"Me, too, Iwa-chan," Oikawa replies, completely having turned Iwaizumi's game of mutual "hate" around on him.

The group finds a booth and sits down. Yukio takes Kise's order, and Iwaizumi already knows what to get Oikawa (a side-effect from having known him for so long), and then the next dilemma emerges:

To leave Oikawa and Kise at the table or not?

Too dangerous, the cousins automatically decide. Oikawa seems to read the situation and goes with Yukio to get the food, leaving Iwaizumi alone at the table with Kise.

"So, senpai's cousin, huh?" Kise prompts.

Iwaizumi nods. "Our moms are sisters. We'd play together during the summer when we were little, but that got harder when we grew older with school and sports and stuff. I'm from Miyagi," he elaborates.

Kise nods his understanding. "Wow… Is it really like the country out there?"

"Nah. It's just quiet."

Kise's got hazel eyes that make Iwaizumi wonder if, along with the blond hair, Kise's half European or something. Those eyes soften as they drift to the order counter. "Senpai in the country… I can picture it, with his guitar."

Iwaizumi's a little taken aback. He remembers Yukio telling him about the impulsive newbie who became a starter for Kaijou almost right away. But to think that Yukio would've grown so close to him that Kise would know about Yukio's guitar-playing? …it's stunning, to be honest. And it kind of makes Iwaizumi smile, just a bit, because he knows Yukio's been friends with Moriyama and Kobori since middle school, but Yukio's never warmed up to anyone so quickly or deeply before.

Kise may be an idiot, but he must be special.

As for Iwaizumi… His eyes sidle over to the counter where Oikawa and Yukio, for some unknowable reason, share a laugh. Oikawa. Sometimes the thought of him gives Iwaizumi a stomachache. Other times…

Oikawa's head shifts, ever so slightly, and he glances at Iwaizumi out of the corner of his eye. Even though his attention's on Yukio, he gives Iwaizumi the tiniest of smiles, which is enough to turn that sudden stomachache into butterflies.

_Fuck_. Things were so much better when Iwaizumi got into arguments with Oikawa. But why had university changed them so much? Why had university meant they'd be around each other almost twenty-four–seven? Why had university meant that saying "I hate you" so often to each other translated into kisses and touches and make-out sessions and Oikawa always making sure his hand was there behind Iwaizumi's head and Iwaizumi being careful about Oikawa's back and—

Iwaizumi stops himself. Such things were _not_ good things to think about while out and about.

Kise sighs and draws the older male's attention back to him.

"I really wish I could've known Yukio-senpai earlier…," he mumbles.

Iwaizumi quirks an eyebrow at him, and Kise turns an amusing reddish color—not cherry red like Yukio earlier, but something of a salmon hue.

"I-I mean—"

"It's fine," Iwaizumi assures him. "He talks a lot about you, Kise. He dotes on you. He cares."

The heat of the blond's cheeks simmers to a healthy rose color, and his eyes sparkle as he chuckles at himself. "Thanks. And sorry. I'm supposed to be on my best behavior when we're around others, but sometimes I get so caught up in him. I didn't mean to upset Oikawa-san earlier, either."

But Kise's words rather explain their ridiculousness earlier, and Iwaizumi eyes his best friend as the other two return with the food. Kise caught up in Yukio? Yeah, he can see that.

Oikawa caught up in him? Yeah, he knows that, too.

* * *

"I want to get back out there ASAP," Iwaizumi says as he and his cousin just start to wash their hands in the restroom.

Yukio groans. "I know exactly what you mean…! I couldn't believe them earlier. Ryouta was so good for one moment and then—" Yukio freezes.

"'Ryouta,' huh?"

The point guard freezes and trips over his tongue. "Hajime! I mean—!"

"Yukio, _it's fine_. It's been obvious from early on you liked him."

Yukio curses. "Goddammit… You sound just like Moriyama!"

"Sounds like a smart guy, then." The look he receives is so dry.

Yukio passes him some paper towel and eyes the door. "What about you and Tooru? He and I have only talked a little today, but he's really grown up, more than I thought he would, based on the impression you gave me over the past several months." He waits. He really wants a response.

Iwaizumi curses. "He said something to you, didn't he?"

A grin blooms slowly on Yukio's face. "Honestly, I've known longer than you have how he feels about you."

"That bastard…!"

"Yes, well, there are plenty of reasons why they are and aren't good for us, Hajime, but right now I'm more concerned about us having essentially dropped sodium in water out there. Shall we?"

The cousins exit the men's room to a shocking sight:

_Oikawa and Kise getting along_.

"…I think that frightens me more," Iwaizumi says, suddenly itching to hit the setter.

Unfortunately, the two pretty boys abruptly end their conversation with bright smiles for their respective better halves when the latter two rejoin them. "Shall we go? I still need to buy new sneakers, Iwa-chan," Oikawa says nonchalantly.

"And you wanted to hit the record store, Kasamatsu-senpai," Kise reminds his former captain.

The four exit the restaurant, the cousins wary. Really, sodium in water would've been easier to handle.

Worse yet, Kise and Oikawa snicker about something unbeknownst to the other two. "I'm not always around Tokyo, but we should hang out again sometime, Oikawa-san, Iwaizumi-san," the blond suggests.

Yukio snorts. "Not around Tokyo…? You half live here, with Seirin, Touou, and Shutoku around here!"

"And now you've left me for Tokyo, too, senpai," Kise whines, resting his cheek atop Yukio's head. But Yukio doesn't fight him. Probably because he's given up and is used to it by now.

"I think we'll be seeing more of each other, Ryouta-chan," Oikawa replies, though his eyes are on Iwaizumi.

"'Ryouta-chan'?" Yukio echoes. He's irked worse than before when Oikawa called Kise Yukio's Oikawa Tooru.

(And Iwaizumi only gets the reference in that moment. Damn Oikawa. Kise as the Oikawa to Yukio's Iwaizumi. Of course. He'll have to smack this brat later.)

But Oikawa and Kise just beam at each other. Clearly they aren't going to reveal which secrets they shared.

The cousins make plans to join up again—maybe with Yukio's other friends, Moriyama and Kobori, even, to wit Oikawa whines about suddenly wanting to see Hanamaki and Matsukawa, as well—and then the volleyball players finally head to the store and start looking for shoes. It's amazing how far removed from their original plan they got.

"Let's be quick about this," Iwaizumi says. "I wasn't planning on being out all day long."

"Mm-hmm," Oikawa mutters. They look at boxes in silence for a beat. "So… Yukio-chan and a high school student."

Ah, right. Yukio had to leave Kise behind at Kaijou, and the poor kid's only a second year.

"They're fucking."

They definitely are, Iwaizumi mentally agrees, though he doesn't want to say it aloud for fear that Oikawa might reveal the details of whatever he and Kise shared. And that would just get Iwaizumi thinking of things it's bad to think about in public.

But he's already thinking of those things, and that things were so much better when they got into arguments. That university has changed them. That university means that they'll be around each other twenty-four–seven. That university means that saying "I hate you" so often to each other translates into kisses and touches and—well, frankly, being themselves.

Huh. Maybe Yukio is right, and things weren't better before. This is just the natural progression for Iwaizumi and Oikawa, and… Well, if Iwaizumi's being honest, he'd admit how they're living right now isn't all that bad. Oikawa's matured. Iwaizumi's matured, too.

"Ah, Iwa-chan, got it," Oikawa announces. He tucks the box under one arm and reaches for Iwaizumi's hand without giving it a moment's thought, just linking their ring fingers and pinkies to tug him along.

Yeah, Yukio's right. There are plenty of reasons why Oikawa Tooru is and isn't good for him.

But Iwaizumi can't find it in himself to care about the reasons why not anymore.

**Author's Note:**

> DAMMIT. Dx Honestly, I love the ship, I do, but it's driving me nuts that Iwaoi/Oiwa isn't even my biggest Haikyuu ship (Ryuuchika/EnnoTana is), and yet I KEEP WRITING THEM. I think it's the Kikasa side-effect, tbh, because those two I can't live without. Kiseeeee! Senpaiiiii! Dx :') I liked the little references to their past, too, like "Kaijou's Kise." ;D *fluffy feels* And the subtle hints those two dorks accidentally dropped that made it easy for Oikawa and Iwa-chan to figure they're dating. And Oikawa's bluntness…! XD Also, I left it intentionally vague as to who tops and who bottoms for Iwaoi/Oiwa (I like to think they take turns, *LOL*), so yeah, whatever. Cousins!Iwaizumi&Kasamatsu is one of the best things ever to have occurred to me, and I'm afraid I might be writing more for them… AGH. HALP.
> 
> Or just leave a review if you'd like more. ;P Thanks for reading, though, and please review! Check out my other HQ! and KnB fics, too!
> 
> -mew-tsubaki :]


End file.
